Question

A body which is at rest but not in equilibrium?

Answer 1

we are looking for an object which will not move for a moment . If we give a force the body will overcome the gravitational force and start moving in the direction of given force . At rest the acceleration was zero for the body therefore it is not in equilibrium. I hope it is helpful.

Answer 2

Thus we are looking for an object that in a particular moment is not moving but it will be moving in the next. ... After a moment, gravity overcomes our provided force and the body starts to move downward in the direction of force. At rest, the acceleration was zero therefore body was in equilibrium.